Title: Integrated Mobile Broadcast (imb) Service Scenarios and System Requirements Document Classification: Unrestricted
Requirements on RF and data transmission in user terminals and in Infrastructure
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- 7.2.2 Filtering requirements
- 7.2.3 Receiver diversity
- 7.2.4 IMB receiver power consumption
- 7.2.5 Component and infrastructure sharing with unicast
- 7.2.6 Efficient data transfer method from BM-SC to RNC, Node-B
- 7.2.7 Independent use of IMB on Non-integrated RAN
- 7.2.8 Concurrent operation of 2G/3G communication and IMB Broadcast receiver
- 7.2.9 LTE-Based IMB
7.2 Requirements on RF and data transmission in user terminals and in Infrastructure7.2.1 Dual mode, Multi Frequency, Dual receiver (multicarrier)Different parts of the world are using different bands for 3G and 2G services. Most popular bands for 3G are 2100 MHz, 850 MHz and 1700 MHz; and for 2G, 850, 900 and 1800 MHz. As IMB will require unicast support (over 3G or 2G networks today and LTE networks in the future), it should be available with user terminals which support 3G and 2G services in these bands. The user terminals should be able to support dual receiver capability since one of the key features of IMB is to deliver the MBMS traffic on a separate unpaired spectrum (TDD) simultaneously without affecting the service performance on the paired spectrum (FDD). The equipment/handset vendors, therefore, ought to ensure that there is minimal impact on the quality of the downlink (TDD) reception when the same device is doing an uplink (FDD) transmission. The frequency selectivity required to protect IMB will likely be built into general purpose WCDMA duplexers, which might be fitted to both IMB and non-IMB handsets in the future, this will help enable the operation of dual receiver capabilities in handsets. Initially IMB handsets may be designed with a separate chip set and RF sections dedicated to IMB. As integration advances the RF section may be shared with W-CDMA, giving cost and space savings. As volume rise the IMB technology will integrated in the W-CDMA chipset as well giving a fully integrated broadcast solution alongside W-CDMA 7.2.2 Filtering requirementsGiven that 1900-1920 MHz TDD band is very close to 3G FDD Uplink frequency at 1920-1925 MHz, appropriate filtering mechanisms will be required both at the node-B and in the devices to enable simultaneous interference free operation of both IMB and 3G services. Handset form factor filters are feasible and have been developed. These filters make use of advances in bulk acoustic wave technology which is now in widespread usage in handset design. In particular the filtering required on the FDD transmit frequency in the handset can be incorporated in the existing duplexer with the same footprint such that there are no additional components and no significant impact on WCDMA performance. 7.2.3 Receiver diversityTo maximise no. of channels possible with IMB or any other form of MBMS, many radio level features are needed to be included in the user terminals design. In particular, receiver diversity enhances the performance significantly. It is therefore desirable that receiver diversity be available in IMB devices although not necessary for initial deployment. This is in step with the roadmap for normal 3G handsets which will incorporate receiver diversity in upcoming releases. However due to the requirement of concurrent support of both 2G/3G communication and IMB, two sets of RF circuit and antenna are necessary in any case. To make the handset and the entire system work in a cost efficient manner, it is recommended to use the two antennas to provide the Receiver Diversity effect to enhance the performance, when either 2G/3G communication or IMB is working solely. Whenever the need arises to support 2G/3G communication and IMB concurrently, then, the each of the two antennas should serve for one service individually, and Receiver Diversity effect should be lost. 7.2.4 IMB receiver power consumptionIMB receiver power consumption should be comparable to or less than the power consumption required for other broadcast technologies such as DVB-H, ISDB-T. Latest DVB-H or ISDB-T TV phones ensure five to six hours of TV watching time. By considering live sport broadcast watching, the device should be able to receive broadcast traffic for at least two hours without re-charging the battery. 7.2.5 Component and infrastructure sharing with unicastAs IMB is to a large extent based on MBMS in the FDD technology, many subsystems are common. The architecture of both devices and Node-Bs should be such that wherever possible common subsystems are reused between unicast and broadcast thus avoiding duplication. Examples of this are device media players, MBMS protocol stack in both the device and the network based elements, some of the baseband components in the devices and in the Node-B and BM-SC etc. For handset terminals with dual receivers, there could be a possibility of components sharing/reuse within the same device between the FDD and TDD technologies although some levels of duplication may also be necessary due to the simultaneous operation of the two technologies. With TDD spectrum band (1900-1920Mhz) adjacent to the FDD uplink spectrum band , it offers many opportunities in term of on the UTRAN infrastructure sharing. The antenna systems and the feeder cables can be reused immediately without replacement. With SDR (Software Define Radio) solution, infrastructure vendors are now able to pack different RF technologies into the same chassis of the NodeB. This allows easier deployment by the operators due to similar footprint to existing NodeBs. 7.2.6 Efficient data transfer method from BM-SC to RNC, Node-BConventional MBMS sends the same broadcast data to every RNC one by one. As IMB would take 5Mbps of data traffic constantly, duplication of the same broadcast data transmission from BM-SC to RNC would become significant and impact to the core network unless efficient data transmission is implemented. 7.2.7 Independent use of IMB on Non-integrated RANWhere MBMS is yet to be introduced into a network, the non-integrated RAN scenario is a good option to provide multi-channel real-time streaming service without causing complexity to the existing FDD core network and UE implementation. 7.2.8 Concurrent operation of 2G/3G communication and IMB Broadcast receiverWith the dual receivers, 2G/3G voice and data services should always be available without any problem, while broadcasted contents are being received through IMB circuit. The concurrent operation of two independent channels should be always available. 7.2.9 LTE-Based IMBAs part of 3GPP release-8, IMB availability is one release cycle ahead of standardization of the initial version of LTE-based eMBMS. Due to its tight integration with existing FDD WCDMA unicast networks and technology, IMB is well suited to the delivery of broadcast content with minimum impact on existing network infrastructure and with seamless interworking with existing unicast deployments. This immediate compatibility with WCDMA networks and possibility for short time-to-market allows mobile network operators to satisfy existing demand for mobile broadcast services. In markets without such urgent need, mobile network operators may prefer to wait for the availability of LTE networks with eMBMS instead. 3GPP release-10 is expected to specify LTE deployments sharing a single carrier of up to 20MHz between unicast and eMBMS broadcast services for bothe FDD and TDD LTE variants; specification of LTE deployments with dedicated broadcast carrier (LTE-based IMB) is likely to follow in a later 3GPP release. Both types of LTE deployment are required to support all deployment scenarios and meet all end-to-end system requirements defined in this document for IMB. Essentially it shall be possible to offer all the same services supported by IMB, including ESG and EPG, over LTE unicast, LTE eMBMS with shared carrier or LTE eMBMS with dedicated carrier with equal or possibly even better user experience. As the standardization of LTE eMBMS progresses and as the penetration of LTE-capable user devices increases, network operators with an operational IMB network will need a smooth migration path from IMB to LTE eMBMS. It is desirable to enable the interworking of IMB, 3G/LTE unicast technologies, LTE eMBMS with shared carrier and LTE eMBMS with dedicated carrier in a manner that is transparent to the user, in order to extend the longevity of the network operators’ returns from the IMB network investment. 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